Production of high-value products and advanced biofuels by genetically engineering the cyanobacterium Synechocystis sp. PCC 6803.

Microorganisms, in general, have long been exploited for their natural products, some of which have been used as fuels, commodity chemicals, specialty chemicals, polymers, and drugs. Cyanobacteria, in particular, can produce a range of high-value chemicals and high-energy fuels from sustainable resources. The freshwater model cyanobacterium, Synechocystis sp. PCC 6803 is considered the most popular species for genetic studies and has been modified for the production of several high-value products and biofuels such as cyanophycin and ethanol respectively. However, high-value products currently being produced in cyanobacteria suffer from very low titres when compared to their heterotrophic organisms counterparts (e.g. E. coli and Saccharomyces). On the other hand, when finding suitable fuels replacement, it is essential to develop what are called andldquo;drop in fuel replacementsandrdquo; that do not require refining and do not require engine modifications. Such designer fuels can potentially be produced in Synechocystis through the genetic manipulation of targeted pathways for the direct synthesis of replacements fuels with characteristics suitable for direct engine combustion. This proposal aims to employ genetic engineering tools to tailor the carotenoid biosynthesis pathway of Synechocystis for the synthesis of significant quantities of the high industrial value carotenoid, astaxanthin, which belongs to the terpene family and is reported to have an estimated market price of ~ US$ 200 x106 per year. The isopreniod (also referred to as terpene) biosynthetic pathway of Synechocystis will also be engineered for the production of the isoprenoid-derived designer drop-in fuel replacement farnesene (a C-15 hydrocarbon). Furthermore, genetic engineering tools and techniques will be used to regulate gene expression by down regulating and over expressing certain genes in the pathway of interest and the use of inducible promoter systems in order to allow for maximum gene expression and product accumulation.